The present invention pertains to an improvement in contraception. More particularly, the invention relates to both a novel and useful intrauterine contraceptive device.
It is known in the prior art the presence of an intrauterine device in the uterus of a fertile female can exhibit a high degree of reliability for the inhibition of conception and pregnancy. Moreover, this phenomenon has been medically used for the intentional prevention of conception and pregnancy by inserting a sized and shaped device into the uterus. While some devices have gained wide usage because of their efficiency and low cost, the practical use for these devices for their intended purpose has been associated with serious disadvantages. One such device in commercial use is comprised of a transverse member perpendicular to a dependent member substantially defining a T-shaped device.
One major disadvantage associated with the T-shaped device is its unacceptably high rate of involuntary expulsion from a viable uterus. This expulsion is most frequently a normal daily occurrence. The expulsion is due to sequential changes in the uterine wall during several degrees of contraction, with the energy of muscle tension converted into pressure that exerts a downward and outward force on the device. This force pushes the device totally or partially from the uterus. In partial expulsion, the dependent member is pushed through the cervical os. The overall expulsion rate for this device often exceeds seven percent and unplanned, unwanted pregnancies are associated with its expulsion. Contraception, Vol. 7, No. 6, pages 477 to 489, 1973.